MicroRNA 802 Stimulates ROMK Channels by Suppressing Caveolin-1
MicroRNA 802 Stimulates ROMK Channels by Suppressing Caveolin-1
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DOI：
10.1681/asn.2010090927
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发表时间：
2011-06-01
影响因子：
13.6
通讯作者：
Wang, Wen-Hui
中科院分区：
文献类型：
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作者：
Lin, Dao-Hong;Yue, Peng;Wang, Wen-Hui
饮食中的钾刺激了对醛固酮敏感的远端肾单位ROMK通道的表面表达，但其发生机制尚不完全清楚。在这里，高钾饮食增加了小鼠皮质收集管中microRNA(MiR)802的转录。此外，高钾摄入降低了小窝蛋白-1的表达，其3‘非翻译区含有miR-802的种子序列。在体外，miR-802的表达抑制了小窝蛋白-1的表达，而内源性miR-802的下调则增加了小窝蛋白-1的表达。蔗糖密度梯度离心法显示小窝蛋白-1与ROMK通道结合紧密，免疫沉淀显示小窝蛋白-1与ROMK的N端相互作用。小窝蛋白-1的表达与ROMK1在质膜上的表达成反比，并且小窝蛋白-1抑制ROMK1通道的活动。从ROMK1中去除依赖于笼蛋白的内吞基序并不能消除小窝蛋白-1对ROMK1通道活性的影响。最后，miR-802的表达增加了ROMK1通道的活性，这种作用被小窝蛋白-1的共表达所阻断。综上所述，miR-802通过抑制小窝蛋白-1的表达来介导高钾饮食对ROMK通道活性的刺激作用，从而导致远端肾单位ROMK通道表面表达增加。
Dietary potassium stimulates the surface expression of ROMK channels in the aldosterone-sensitive distal nephron, but the mechanism by which this occurs is incompletely understood. Here, a high-potassium diet increased the transcription of microRNA (miR) 802 in the cortical collecting duct in mice. In addition, high-potassium intake decreased the expression of caveolin-1, whose 3' untranslated region contains the seed sequence of miR-802. In vitro, expression of miR-802 suppressed the expression of caveolin-1, and conversely, downregulation of endogenous miR-802 increased the expression of caveolin-1. Sucrose-gradient centrifugation suggested that caveolin-1 closely associated with ROMK channels, and immunoprecipitation showed that caveolin-1 interacted with the N terminus of ROMK. Expression of caveolin-1 varied inversely with the expression of ROMK1 in the plasma membrane, and caveolin-1 inhibited ROMK1 channel activity. Removal of the clathrin-dependent endocytosis motif from ROMK1 failed to abolish the effect of caveolin-1 on ROMK1 channel activity. Last, expression of miR-802 increased ROMK1 channel activity, an effect blocked by coexpression of caveolin-1. Taken together, miR-802 mediates the stimulatory effect of a high-potassium diet on ROMK channel activity by suppressing caveolin-1 expression, which leads to increased surface expression of ROMK channels in the distal nephron.